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  <div class="section" id="old-buffer-protocol">
<h1>Old Buffer Protocol<a class="headerlink" href="#old-buffer-protocol" title="Permalink to this headline">¶</a></h1>
<div class="deprecated">
<p><span class="versionmodified">Deprecated since version 3.0.</span></p>
</div>
<p>These functions were part of the “old buffer protocol” API in Python 2.
In Python 3, this protocol doesn’t exist anymore but the functions are still
exposed to ease porting 2.x code.  They act as a compatibility wrapper
around the <a class="reference internal" href="buffer.html#bufferobjects"><span class="std std-ref">new buffer protocol</span></a>, but they don’t give
you control over the lifetime of the resources acquired when a buffer is
exported.</p>
<p>Therefore, it is recommended that you call <a class="reference internal" href="buffer.html#c.PyObject_GetBuffer" title="PyObject_GetBuffer"><code class="xref c c-func docutils literal"><span class="pre">PyObject_GetBuffer()</span></code></a>
(or the <code class="docutils literal"><span class="pre">y*</span></code> or <code class="docutils literal"><span class="pre">w*</span></code> <a class="reference internal" href="arg.html#arg-parsing"><span class="std std-ref">format codes</span></a> with the
<a class="reference internal" href="arg.html#c.PyArg_ParseTuple" title="PyArg_ParseTuple"><code class="xref c c-func docutils literal"><span class="pre">PyArg_ParseTuple()</span></code></a> family of functions) to get a buffer view over
an object, and <a class="reference internal" href="buffer.html#c.PyBuffer_Release" title="PyBuffer_Release"><code class="xref c c-func docutils literal"><span class="pre">PyBuffer_Release()</span></code></a> when the buffer view can be released.</p>
<dl class="function">
<dt id="c.PyObject_AsCharBuffer">
int <code class="descname">PyObject_AsCharBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, const char<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsCharBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a read-only memory location usable as character-based
input.  The <em>obj</em> argument must support the single-segment character buffer
interface.  On success, returns <code class="docutils literal"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <code class="docutils literal"><span class="pre">-1</span></code> and sets a
<a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_AsReadBuffer">
int <code class="descname">PyObject_AsReadBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, const void<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsReadBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a read-only memory location containing arbitrary data.
The <em>obj</em> argument must support the single-segment readable buffer
interface.  On success, returns <code class="docutils literal"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location
and <em>buffer_len</em> to the buffer length.  Returns <code class="docutils literal"><span class="pre">-1</span></code> and sets a
<a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_CheckReadBuffer">
int <code class="descname">PyObject_CheckReadBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*o</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_CheckReadBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns <code class="docutils literal"><span class="pre">1</span></code> if <em>o</em> supports the single-segment readable buffer interface.
Otherwise returns <code class="docutils literal"><span class="pre">0</span></code>.</p>
</dd></dl>

<dl class="function">
<dt id="c.PyObject_AsWriteBuffer">
int <code class="descname">PyObject_AsWriteBuffer</code><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject">PyObject</a><em>&nbsp;*obj</em>, void<em>&nbsp;**buffer</em>, Py_ssize_t<em>&nbsp;*buffer_len</em><span class="sig-paren">)</span><a class="headerlink" href="#c.PyObject_AsWriteBuffer" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns a pointer to a writable memory location.  The <em>obj</em> argument must
support the single-segment, character buffer interface.  On success,
returns <code class="docutils literal"><span class="pre">0</span></code>, sets <em>buffer</em> to the memory location and <em>buffer_len</em> to the
buffer length.  Returns <code class="docutils literal"><span class="pre">-1</span></code> and sets a <a class="reference internal" href="../library/exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal"><span class="pre">TypeError</span></code></a> on error.</p>
</dd></dl>

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